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Name the two main division sof hte peripheral nervous system
  • Somatic: sends motor signals to skeletal muscles
  • Autonomic: Further brokcen down into Sympathetic and parasympathetic
Describe the parasympathetic division of the autonomic nervous system in terms of length of pre and post ganglions, types of receptors, and neurotransmitters used.
Preganglionic: Long
postganglionic: short
Receptors: nicotinic and Muscarinic
Neurotransmitter: ACh
Describe the Sympathetic division of hte autonomic nervous system in terms of length of pre and post ganglions, types of receptors, and neurstrasnmitters used
preganlgionic: short
Postganglionic: long
Receptors: Adrenergic and Nicotinic
Neurotransmitters: ACh, NE, Epi
The Adrenal Medulla is innervated by waht division of the peripheral nervous system
The Sympathetic preganglionic nerves (then it releases NE and Epi)
the peripheral nervous system has 2 main divisons: Somatic and autonomic.  what does the somatic divison do?
MOTOR:  It innervates skeletal muscles (sends motor impulses to skeletal muscles and carry impulses of touch, pressure, temperature pain, to the spinal cord)
What is the neurotransmitter released from somatic motor nerves?
AcH (at the neuromsucluar juntion-- Nicotinic receptors)
NE is the neurotransmitter released from all of the Sympathetic postganglionic nerves except one.  What is it?
the sweat glands.  AcH is released from the sympathetic postganglionic nerves at the sweat glands
Muscarinic receptors are found peripherally in tissues innervated by: parasympathetic or sympathetic?
Nicotinic Receptors are found 3 places in the body.  (AcH is the neurostransmitter in all 3 places)
Name them
  • Skeletal muscle motor end plate (Somatic division of PNS)
  • Adrenal medulla (sympathetic rel. AcH here and Adrenal medulla released NE or Epi)
  • Autonomic Ganglia (where the preganlionic neurons synapse with the postganglinic neurons)
What is a Phase II Block?
this is when the nicotinic receptor at the neurosmuscular juncion becomes inexcitable due to prolonged exposure or high doses of succinylcholine
What type of channel is the nicotinic receptor?
Ligand activated channel: when 2 AcH molecules attach to the receptor, the channel snaps open and Na and Ca diffuse inot the cell and K diffuses OUT.
A Alpha Fibers: size & function
largest, myelinated (fastest conduction of impulses)
they are somatic motor nuerons so the they carry motor and sensory signals ot skeletal muscle and joints
What nerve fibers carry sensations of sharp pricking pain, temperature, touch
A Delta fibers
C fibers carry impulses for what division  of the peripheral nervous system?
sympathetic (postganglionic)
which fibers are faster myelinated or unmyelinated?
Motor nerves are mostly what: A, B or C nerve fibers?
A: largest and fastest
A alpha: effeceretn motor signals (force and length)
A beta: proprioception
A delta: pricking pain
List the number of vertebrea: cervical thoracic, lumbar an sacral
C 8
T 12
L 5
S 5
What is another name for sympathetic nervous system/outflow
Thoracolumbar outflow (T1 -L2/3)
Cardiac accelerator fibers arise from where in the spinal cord?
What are S/S of Horner's Sydrome?
Ipsilateral ptosis (droopy eyelid), miosis (pupil constriction), enopthalamos, flushing, increased skin temperature, anhydrosis (loss of ability to sweat), and nasal congestion
What is Horner's Syndrome
This is due to Stellate Ganglion Blockade
The stellate Ganglion is formed by the inferior cervical and first thoracic ganlgia, so if you have sympathetic block that extends beyond the throacic vertebrea, it could cause horner's syndrome.
What is the Stellate Ganglion?
Formed by the inferior cervical and first thoracid ganglia.  Blockade of this area casues horner's syndrome
What is the first sign of a high spinal in a neonate?
All preganglionic sympathetic fibers pass through _____
White Rami
What happens when presynaptic alpha2 receptors are stimulated by NE or an alpha2 receptor agonist?
the synthesis and release of NE is decreased (negative feedback)
How is norepinephrine made?
  • tyrosine is transported inot the nerve terminal from the bloodstream
  • Tyrosine is converted to Dopa
  • Doap is converted to dopamine
  • Dopamine transp0orted inot th epresynapltic vescicle
  • Dopamine is converted to norepinephrine
In the Adrenal medulla, what % of Nurotransmitters are norepi and epi
20% Norepi
80% Epi
What cause the release of Noreponephrine form the postganglionic neuron into the synaptic cleft?
An action potential travels along the axon---depolarization causes the Ca channels to open and Ca diffuses into the cell---this causes exocytosis of NE into the synaptic cleft
What elecrolyte is needed to diffuse into the cell to cause the release of norepineprine?
What is the first step in the termination of action of norepinephrine?
diffusitonof norepinephrine (ligand) away from the receptor
What 3 things can happen to norepinephrine after it diffuses away from the receptor?
  • 80% is returned to the nerve terminal (reuptake)
  • metabolism by MAO in the synaptic cleft
  • diffuse into bloodstream to be metabolized by COMT
What 2 drugs should be avoided in the patient takin MAO inhibitors and why?
Ephedrine and Demerol
Both of these drugs trigger the release of norepinephrine.
since the pt is taking an MAO inhibitor and MAO metabolizes norepinephrine, the pt is at risk for excess amount of NE to be released and a hypertensive crisis could result.
How do indirect acting sympathomimetics work?
they displace norepinephrine ffrom sympathetic nerve termnals (so it get released and attaches to the receptor on the postsynsaptic neuron)\
Ephedrine does this (it also is a direct acting sympathomimetic)
Where are Alpha1 receptors and what do they do?
vascular smooth muscle and glands
produce arterial and venous constriction

What is varicosity
it is the site of synthesis and release of noreponephrine (in a sympathetic postganglionic neuron)
What receptors does Clonidine work on?
Alpha2 receptos in the substantia gelatinosa (in th espinal cord) to promote analgesia
what neurotransmitter do MAOs metabolize?
What 2 things have the ability to metabolize norepinephrine?
Monoamine oxidase (in the synaptic cleft)
COMT (in the bloodstream)
Where are Alpha1 receptors found and what do they do?
Pupil of the eye -- dilate it (mdriases)
Veins -- Vasoconstriction
Ateries -- vasoconstriction
kidney -- decrease Renin release
Where are Alpha2 receptors found and what do they do?
  • Presysnaptic nerve terminals of postganglionic neurons -- negative feedback: decreases the release of norepinephrine
  • Brainstem: Inhibits outflow of the sympathetic nervous system
  • Substantia Gelatinosa of the spinal cord: analgesia
Where are Beta1 receptors found and what do they do?
  • Stimulation is Excitatory
    SA node (inrease HR), AV node (increase conduction speed), Muscle fibers increase contractiity)
  • Kidneys: decrease renin production
  • Adipose tissue: lipolysis
Where are Beta2 receptors found and what do they do?
  • Stimulation is Inhibitory
    skeletal  muscle vessels:
    Lungs: Bronchodilation, increase secretions
  • Liver: increase blood sugar
  • Sodium-Potassium pump: activates it so promotes K going inot the cell
  • Uterus: relaxation
Does Beta2 stimulation promote hypoglycemia or Hyperglycemia?
Hyperglycemia b/c it increaseses glycogenolysis (glycogen to glucose) and gluconeogenesis (CHO to glucose)
List 3 side effects of beta2 Agonists
  • Hyperglycemia
  • Hypokalemia (activates Na K pump
  • Tachycardia (b/c these drugs have some beta1 effects)
85% of resting blood pressure is controlled by _____
Where is Renin released from? in response to what?
the Juxtamedullary (JG) cells of the afferent arteriole in the kidney in response to decreased renal artery blood pressure or sympathetic nerve activity
What does Renin do?
It converts angiotensinogen to Angiotensin I
What does Angiotensin II do?
Promotes vasocontriction and the release of Aldosterone
What does Aldosterone do?
Increases Potassium excretion and
Na reabsorption = promotes fluid rentention (volume expansion)
What adrenergic receptors does phenylephrine work on?
Alpha1 (vasoconstricts blood vessels)
no effect on beta receptors
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